In recent years, an augmented reality technology has become known in which a virtual image is projected onto an actual object using a projector, and annotations, menus, and the like that are associated with the actual object are presented. In addition, in the augmented reality technology such as this, a user interface technology is used in which a gesture made by a manipulating object, such as a hand and fingers, is detected and interaction with a virtual image is actualized.
As a method for detecting such gestures made by the manipulating object, for example, P. Mistry, P. Maes, “Sixth Sense—A Wearable Gestural Interface” in the Proceedings of SIGGRAPH Asia 2009, Emerging Technologies, Yokohama, Japan, 2009 discloses a method for measuring three-dimensional coordinates of the manipulating object using captured images of the manipulating object that have been captured by a camera, and detecting a gesture based on changes in the three-dimensional coordinates.